Dynamic molecular design for liquid-crystalline materials with a fast response speed

1.液晶显示材料的研究进展：制备了一种新型的U型液晶分子1-{6-（3，4-二氟苯氧基）己氧基}-2-{6-[4-（4-氟苯基）苯氧基]己氧基}苯，并研究了其电光性能。由主体液晶和10wt%的U型化合物组成的混合物的阈值电压被发现明显低于主体液晶的阈值电压。阈值电压的显着降低的化合物被认为是由于介电各向异性的增加。U型体系是降低液晶材料阈值电压的新途径。2.具有宽蓝相区的新型手性液晶：设计了具有分子双轴性的手性液晶低聚物。我们制备了（R）-2，2 '-双{6-[4-（2-（2-氟-4-丁氧基苯基）嘧啶-5-基）苯氧基]烷氧基}-1，1'-二氧代-N-（2-氟-4-丁氧基苯基）嘧啶-5-基）苯氧基的同系物。 关于我们 联萘间隔基中原子数为偶数的联萘衍生物显示出手性双相，而原子数为奇数的联萘衍生物在各向同性和SmA相之间的较宽温度范围内显示出蓝相.然后，我们制备了T形化合物，（R）-1-甲基庚基-4 '-{4-辛氧基-2-{11-[4-甲基庚基]-2-基}-1-甲基庚基-4'-酮。（5-辛基嘧啶-2-基）苯氧基]十一烷酰氧基}苯甲酰氧基}联苯-4-羧酸酯，发现其在冷却时显示具有宽温度范围的蓝相。合成了一系列新颖的λ型介晶化合物，其中3个介晶基团连接到3，4-二羟基苯甲酸上。发现3，4-双{6-[4-（5-辛基嘧啶-2-基）苯氧基]己氧基}苯甲酸4-氰基联苯-4 '-基酯实现了无公度SmA（SmAinc）相。合成了一系列同系双介晶液晶α-（4-氰基联苯-4 '-氧基）-ω-[4-（5-烷基嘧啶-2-基）苯基-4”-氧基]烷烃（mPYnOCB）。发现具有不同奇数间隔基的双介晶化合物在某些二元混合物中可诱导出叉指型的背斜近晶C（SmCanti）相。此外，在垂直排列的样品的SmCanti相中观察到条纹图案。当样品的温度变化时，条纹图案传播。少

1.Development of nematic liquid crystals for display devices : A novel U-shaped liquid-crystalline molecule where two polar mesogenic groups are connected via catechol,1-{6-(3,4-difluorophenyloxy)hexyloxy}-2-{6-[4-(4-fluorophenyl)phenyloxy]hexyloxy}benzene, was prepared and the electrooptic properties were investigated. The threshold voltage of a nematic mixture consisted of a host liquid crystal (LC) and 10wt% of the U-shaped compound was found to be markedly lower than that of the host LC. Marked reduction in threshold voltage by the compound was found to be attributed to the increase in dielectric anisotropy. The U-shaped system is a novel approach for the reduction in the threshold voltage of liquid-crystalline materials.2.Novel chiral liquid crsyatls with a broad blue phase region : We designed chiral liquid crystal oligomers possessing molecular biaxiality. We prepared a homologous series of (R)-2,2'-bis{6-[4-(2-(2-fluoro-4-butyloxyphenyl)pyrimidine-5-yl)phenyloxy]alkyloxy}-1,1'- … More binaphthyl. The binaphthyl derivatives with an even number of atoms in the spacers showed a chiral nematic phase, however, those with an odd number of atoms showed a blue phase in a relatively wide temperature range between the isotropic and SmA phases. Then, we prepared a T-shaped compound, (R)-1-methylhepthy1-4'-{4-octyloxy-2-{11-[4-(5-octylpyrimidin-2-yl)phenoxy]undecanoyloxy}benzoyloxy}biphenyl-4-carboxylate, which was found to show a blue phase with a wide temperature range on cooling.3.Liquid crystal oligomers with a hierarchical structure : A homologous series of novel λ-shaped mesogenic compounds in which three mesogenic groups are connected to 3,4-dihyrdoxybenzoic acid has been prepared. 4-Cyanobiphenyl-4'-yl 3,4-bis{6-[4-(5-octylpyrimidm-2-yl)phenyloxy]hexyloxy}behzoate was found to realize an incommensurate SmA (SmAinc) phase. We prepared a homologous series of bimesogenic liquid crystals, α-(4-cyanobiphenyl-4'-yloxy)-ω-[4-(5-alkylpyrimidine-2-yl)phenyl-4"-oxy]alkane (mPYnOCB). The interdigitated anticlinic smectic C (SmCanti) phase was found to be induced for some binary mixtures betweeen the bimesogenic compounds with a different odd-numbered spacer. Furthermore, a striped pattern was observed in the SmCanti phase of a homeotropically aligned sample. The striped pattern was propagated when the temperature of the sample was varied. Less